Pret A Manger has introduced its 50p discount to encourage more customers to bring reusable coffee cups into its sites.
Chief executive Clive Schlee said he hoped the initiative would make a difference.
Last month he said the company had also considered charging customers for using paper cups but felt the move would go “against its instincts”.
He said that it also plans to explore offering more china cups in its sit-down stores and launching its own reusable cup next year.
Writing in his blog last year, he said: “I was inundated with suggestions, ideas and feedback. Here are five highlights – 96% of the 5,000 respondents to an Instagram Stories poll voted ‘yes’ to the 50p idea. A great many customers recommended we sell a branded reusable cup as well as launching the new discount.
“Lots suggested we turn the discount on its head and charge for cups instead. The economic theory of loss aversion was mentioned – this says people respond to loss or fear of a penalty much more than they do to a reward or discount.
“The success of the government’s 5p bag charge was cited as evidence of how effective this can be.
“A handful of people pointed out china cups ought to be available in more of our shops. It was suggested we set up a loyalty scheme tied to reusable cups. Some wanted us to implant chips into the cups themselves that could measure usage and automatically apply a discount.
“On the basis of this feedback, Pret is going to do three things – launch the 50p discount in the first week of 2018; source a well-designed reusable cup ready to launch later in 2018; and explore adding china cups to more of our shops with seats. We debated whether charging people for using paper cups felt right.
“We decided it goes against our instincts as we would prefer to be generous to our customers than tax them. Let’s see what impact the new discount has. Thank you for helping us move forwards!”